Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0075—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for altering, e.g. increasing, the depth of field or depth of focus
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
  • G03G15/04036—Details of illuminating systems, e.g. lamps, reflectors
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/08—Anamorphotic objectives
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/24—Optical objectives specially designed for the purposes specified below for reproducing or copying at short object distances
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/24—Optical objectives specially designed for the purposes specified below for reproducing or copying at short object distances
  • G02B13/26—Optical objectives specially designed for the purposes specified below for reproducing or copying at short object distances for reproducing with unit magnification
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
  • G02B3/0006—Arrays
  • G02B3/0037—Arrays characterized by the distribution or form of lenses
  • G02B3/005—Arrays characterized by the distribution or form of lenses arranged along a single direction only, e.g. lenticular sheets
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
  • G02B3/0006—Arrays
  • G02B3/0037—Arrays characterized by the distribution or form of lenses
  • G02B3/0062—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
  • G03G15/04036—Details of illuminating systems, e.g. lamps, reflectors
  • G03G15/04045—Details of illuminating systems, e.g. lamps, reflectors for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers
  • G03G15/04054—Details of illuminating systems, e.g. lamps, reflectors for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers by LED arrays
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
  • G03G15/04036—Details of illuminating systems, e.g. lamps, reflectors
  • G03G15/04045—Details of illuminating systems, e.g. lamps, reflectors for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers
  • G03G15/04063—Details of illuminating systems, e.g. lamps, reflectors for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers by EL-bars
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G15/00—Apparatus for electrographic processes using a charge pattern
  • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
  • G03G15/043—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for controlling illumination or exposure
  • G03G15/0435—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for controlling illumination or exposure by introducing an optical element in the optical path, e.g. a filter
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/024—Details of scanning heads ; Means for illuminating the original
  • H04N1/02409—Focusing, i.e. adjusting the focus of the scanning head
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/024—Details of scanning heads ; Means for illuminating the original
  • H04N1/02418—Details of scanning heads ; Means for illuminating the original for picture information pick up and reproduction
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/024—Details of scanning heads ; Means for illuminating the original
  • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
  • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
  • H04N1/0282—Using a single or a few point light sources, e.g. a laser diode
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0018—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for preventing ghost images

Definitions

• the present invention relates to an optical apparatus, and more particularly an optical apparatus suitably applied to an image forming apparatus or image reading apparatus, for example.
• image forming apparatuses and image reading apparatus including optical apparatuses which have a lens array made up of multiple lenses.
• This configuration enables realization of reduction in apparatus size and costs, in comparison with configurations scanning a photosensitive member by a polygon mirror, configurations reading images using multiple lenses and mirrors, and so forth.
• PTL 1 discloses a lens array in which multiple lenses are arrayed in one direction (first direction) .
• Each of the multiple lenses perform erecting same-size imaging of an object within a cross-section parallel to the first direction and optical axis direction (first cross-section), and perform inverted same-size imaging of an object within a cross-section perpendicular to the first direction (second cross-section) .
• This configuration enables the lens power to be smaller within the second cross-section, as compared with an optical system performing erecting same-size imaging in the first cross-section. This is advantageous in
• Depth of field indicates a range on the optical axis over which a predetermined resolution can be obtained in front of and behind the image field position. Normally, a lens array having a great depth of field has lower light available efficiency, and a lens array having great light available efficiency has lower depth of field. Further, a lens array has to have resolution ensured within the first and second cross-sections, so consideration has to be given to common field of depth within both cross-sections.
• the lens array disclosed in PTL 1 does not take into consideration the common depth of field within both the first and second cross-sections when receiving input of light rays from the light-emission points of an array light source. That is to say, the lens array
• the lens array disclosed in PTL 1 is not an optimal configuration for realizing both resolution and light available efficiency, since light available efficiency is lost by the amount exceeding the common depth of field at one cross-section.
• the common depth of field of the lens array differs according to the position of each light-emitting point of the array light source, as well. Accordingly, difference in light-emitting point has to be taken into consideration to realize both resolution and light available efficiency, but there is no disclosure or suggestion of taking difference in light-emitting point with regard to the lens array described in PTL 1.
• An optical apparatus includes: a light source including a plurality of light-emitting points arrayed in a first
• an imaging optical system including a
• the imaging optical system forms images f the plurality of light-emitting points on a light-receiving surface.
• 0 m represents a half-value of a maximum value of angle of divergence (aperture angle) of an imaging optical flux input to the light-receiving surface
• P m represents resolution
• D m represents a size of each image of the plurality of light-emitting points, formed on the light-receiving surface
• ⁇ 3 represents a half-value of a maximum value of angle of divergence (aperture angle) of an imaging optical flux input to the light-receiving surface, P s
• D s represents a size of each image of the plurality of light-emitting points, formed on the light-receiving surface.
• FIGs. 1A through 1C are schematic diagrams of principal portions of an optical apparatus according to a first embodiment.
• Fig. 2 is a conceptual diagram for describing depth of field.
• Figs. 3A through 3D are diagrams illustrating the way in which light-emitting points according to the first embodiment are imaged.
• Figs. 4A and 4B are diagrams for describing how depths of field are arrayed.
• FIGs. 5A and 5B are diagrams illustrating depth of field properties of an imaging optical system according to the first embodiment.
• FIGs. 6A and 6B are diagrams illustrating depth of field properties of an imaging optical system according to a second embodiment .
• Figs. 7A through 7D are diagrams illustrating the way in which light-emitting points according to a third embodiment are imaged.
• FIGs. 8A and 8B are diagrams illustrating depth of field properties of an imaging optical system according to the third embodiment.
• Fig. 9 is a diagram illustrating the relationship between object height and light available efficiency of a lens optical system according to the third embodiment.
• Figs. 10A through 10D are diagrams illustrating the way in which light-emitting points according to a fourth embodiment are imaged.
• FIGs. 11A and 11B are diagrams illustrating depth of field properties of an imaging optical system according to the fourth embodiment.
• Figs. 12A through 12D are diagrams illustrating the way in which light-emitting points according to a fifth embodiment are imaged.
• FIGs. 13A and 13B are diagrams illustrating depth of field properties of an imaging optical system according to the . fifth embodiment.
• FIGs. 14A through 14C are schematic diagrams of principal portions of an optical apparatus according to a sixth embodiment.
• Figs. 15A through 15D are diagrams illustrating the way in which light-emitting points according to the sixth embodiment are imaged.
• FIGs. 16A and 16B are diagrams illustrating depth of field properties of an imaging optical system according to the sixth embodiment.
• Fig. 17 is a schematic diagram of principal
• FIGs. 1A through 1C are schematic diagrams of principal portions of an optical apparatus according to a first embodiment applied to an image forming apparatus.
• Fig. 1A illustrates a first cross-section (X-Y cross-section)
• Fig. IB illustrates a second cross-section (Z-X cross- section)
• Fig. 1C is a frontal view from the optical axis direction (X direction) .
• the optical apparatus
• a light source 101 including multiple light-emitting points arrayed on an object plane, and an imaging optical system 105 which
• the light source 101 includes multiple light- emitting points arrayed at equal intervals in a first
• a photosensitive member such as a photosensitive drum is disposed at the light- receiving surface 106.
• a document is positioned instead of the light source 101, and a photoreceptor sensor (line sensor) such as a CMOS sensor or the like is positioned at the light-receiving surface 106 instead of a photosensitive member.
• a photoreceptor sensor line sensor
• CMOS sensor complementary metal-oxide-semiconductor
• the imaging optical system 105 is a lens array including imaging units 102 and 104 which include multiple lens units arrayed in the first direction, and shielding portions 103 to shield stray light rays.
• the imaging units 102 and 104 are configured having one row in the second direction (Z direction) of a lens row where multiple lens portions of the same shape are arrayed at equal intervals in the first direction, as illustrated in Fig. 1C.
• the lens portions in imaging units 102 and 104 which are disposed on the same optical axis will be collectively described as lens optical system 105a.
• Lens surfaces 102a, 102b, 104a, and 104b of the lens optical system 105a all have anamorphic aspheric forms
• the shielding portions 103 serve to allow, of the light rays passing through the imaging unit 102, light rays that contribute to imaging to pass through, and shield stray light rays not contributing to imaging. In the following description, the thickness (width in second direction) of the shielding portions 103 is excluded from consideration .
• the lens portions of the imaging unit 102 condense the multiple light rays emitted from the light source 101 on an intermediate imaging plane A in the first cross-section (X-Y cross-section) parallel to the first direction and the optical axis direction of the lens optical system 105a as illustrated in Fig. 1A.
• the intermediate imaging plane A is an imaginary plane where the imaging unit 102 forms an intermediate image of the light source 101 (object plane), i.e., performs intermediate imaging of the object plane.
• the intermediate imaging plane A exists at an approximately intermediate position between the light source 101 and the light-receiving surface 106 (image plane).
• Light rays temporarily condensed at the intermediate imaging plane A enter each lens portion of the imaging unit 104, and further are condensed at the light-receiving surface 106. That is to say, the imaging unit 104 forms an image of the intermediate image of the light source 101 on the light- receiving surface 106. In other words, the intermediate image is re-imaged upon the light-receiving surface 106.
• the imaging optical system 105 is a system performing erecting same-size imaging of the light- emitting points on the light-receiving surface 106, in the X-Y cross-section, i.e., is an erecting same-size imaging system.
• the imaging optical system 105 in the second cross-section (Z-X cross-section) perpendicular to the first direction, is a system performing inverted same-size imaging of the light- emitting points on the light-receiving surface 106 without performing intermediate imaging, i.e., is an inverted same- size imaging system, as illustrated in Fig. IB. While countless light rays actually are being condensed by the imaging units 102 and 104, only a few characteristic light rays are illustrated in Fig. 1A.
• Fig. 2 is a conceptual diagram illustrating images (200a and 200b) of two adjacent light-emitting points, formed on the light-receiving surface 106, to evaluate resolution as Pi.
• the interval between the two images is set to 1/Pi.
• ⁇ in Fig. 2 represents the distance from the light-receiving surface 106 where the two images 200a and 200b begin to overlap due to defocusing (defocus tolerance value) , which indicates a half-value of the depth of field when the contrast is 100%.
• defocusing defocus tolerance value
• ⁇ is the half-value of the angle of
• the half-value of the angle formed between the light ray on the extreme periphery of the multiple light rays making up the imaging optical flux forming the image 200a, and the light ray on the extreme periphery of the multiple light rays making up the imaging optical flux forming the image 200b, is also ⁇ .
• Transforming Expression (2) yields the defocusing tolerance value ⁇ when contrast is 100%, shown in the following Expression (3) .
• Pi and Di are decided by the printing dot size set at the image forming apparatus (or image reading apparatus) into which the optical apparatus information has been built, and accordingly are constant for each apparatus model and each printing mode.
• the light available efficiency of the imaging optical system 105 is proportionate to the half- value ⁇ of the angle of divergence (aperture angle) of the imaging optical flux, and accordingly is approximately proportionate to tanGi.
• ⁇ is inversely proportionate to tanGi.
• light available . efficiency and depth of field are in an inversely proportionate relationship.
• the aperture size of the lens optical systems 105a in the first and second directions have been designed in the present embodiment so as to satisfy Expression (5) .
• the depth of field in both the X-Y cross- section and Z-X cross-section can be kept from becoming unnecessarily high as to the common depth of field. That is to say, an optimal optical configuration can be achieved to realize both light available efficiency and imaging
• the optical apparatus according to the present embodiment is configured so that the ratio between ⁇ 3 and Ax m is contained within a range of 0.8 to 1.2 as shown in Expressions (4) and (5), taking the effects of placement error and so forth into consideration.
• the ratio between ⁇ 3 and Ax m falls out of the range of
• FIG. 3A is a diagram illustrating the way in which a light-emitting point 101a situated on the optical axis of one lens optical system 105a (hereinafter, referred as "at axial object height") is imaged on the light-receiving surface 106 in the X-Y cross-section.
• Light rays emitted from the light-emitting point 101a are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 102, and subsequently condensed on the light-receiving surface 106 by way of the imaging unit 104.
• the light rays emitted from the light-emitting point 101a each only pass through one lens portion at each of the imaging units 102 and 104.
• the number of lens optical systems 105a which the light rays emitted from the light-emitting point at axial object height pass through is one.
• the half-value of the incident angle of an extreme periphery light ray 107ma of the light rays passing through that lens optical system 105a when entering the light-receiving surface 106 i.e., the half-value of the angle of divergence of the imaging optical flux of the light rays emitted from the light-emitting point 101a, is 6 ma of 7.32 degrees.
• Fig. 3B is a diagram illustrating the way in which a light-emitting point 101b of which light passes through an intermediate position between optical axes of adjacent lens optical systems 105a
• At intermediate object height (hereinafter, referred as "at intermediate object height") is imaged on the light-receiving surface 106 in the X-Y cross-section.
• Light rays emitted from the light-emitting point 101b are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 102, and
• the light rays emitted from the light-emitting point 101b pass through two lens portions at each of the imaging units 102 and 104. That is to say, in the X-Y cross-section the number of lens optical systems 105a which the light rays emitted from the light-emitting point at intermediate object height pass through is two.
• the half-value of the incident angle of an extreme periphery light ray 107mb of the light rays passing through that lens optical system 105a when entering the light-receiving surface 106 i.e., the half-value of the angle of divergence of the imaging optical flux of the light rays emitted from the light-emitting point 101b, is of 13.46 degrees.
• the number of lens optical systems 105a which the light rays emitted from the light-emitting points pass through in the X-Y cross-section differ according to the position of the light-emitting point, so the half-value 0 m of the angle of divergence of the imaging optical flux also changes in accordance with the position of the light- emitting point.
• the maximum (greatest) number of lens optical systems 105a to pass through is for the imaging optical flux emitted from a light-emitting point at
• the half-value 9 m of the angle of divergence of the imaging optical flux formed by light rays from a light-emitting point at intermediate object height (light- emitting point 101b) can be deemed to be the greatest
• the depth of field for an imaging optical flux emitted from a light-emitting point at intermediate object height is the smallest of the light- emitting points of the light source 101.
• the half-value 0 m of the angle of divergence of the imaging optical flux from a light-emitting point at intermediate object height (light-emitting point 101b) is not the maximum.
• the half-value 0 m of the angle of divergence of the imaging optical flux is almost completely decided by the number of lens optical systems 105a through which the imaging optical flux passes, so we can view difference due to the position of light-emitting points being non-existent if the number of thereof is the same.
• the half-value 0 m of the angle of divergence of the imaging optical flux from a light-emitting point at intermediate object height (light-emitting point 101b) is deemed to be the maximum of the multiple light- emitting points in the light source 101 in the present embodiment .
• the imaging optical system 105 here is an inverted same-size imaging system in the Z-X cross- section, so the number of lens rows of the lens optical system 105a which light rays emitted from the light-emitting point 101a pass through is one.
• the number of lens rows in the second direction is one row, so light rays emitted from the light-emitting point 101a only pass through one lens optical system 105a.
• the half-value of the incident angle of an extreme periphery light ray 107sa of the light rays passing through that lens optical system 105a when entering the light-receiving surface 106 i.e., the half-value of the angle of divergence of the imaging optical flux of the light rays emitted from the light-emitting point 101a, is 9 sa of 21.14 degrees.
• light rays emitted from the light-emitting point 101b also only pass through one lens optical system 105a, in the same way as with light rays emitted from the light-emitting point 101a.
• the half-value of the incident angle of an extreme periphery light ray 107sb of the light rays passing through that lens optical system 105a when entering the light-receiving surface 106 i.e., the half-value of the angle of divergence of the imaging optical flux of the light rays emitted from the light-emitting point 101b, is 0 sb of 21.14, the same as with 6 sa -
• the number of lens optical systems 105a which the light rays emitted from the light-emitting points pass through in the Z-X cross-section do not differ according to the position of the light-emitting point with the present embodiment, so the half-value ⁇ 3 of the angle of divergence of the imaging optical flux is constant regardless of the position of the light-emitting point. That is to say, the depth of field is constant regardless of the position of the light-emitting point.
• the depth of field changes at each light-emitting point position in the X-Y cross-section, and the depth of field is constant regardless of the position of the light-emitting point in the Z-X cross-section.
• Figs. 4A and 4B are diagrams for describing two patterns of making the depth of field the same.
• Figs. 4A and 4B illustrates defocusing tolerance values corresponding to each light-emitting point in the X-Y cross-section, connected by dotted lines -Ax m and +Ax m , and illustrates defocusing tolerance values corresponding to each light- emitting point in the Z-X cross-section, connected by solid lines - ⁇ 3 and + ⁇ 3 .
• the intervals between the dotted lines -Ax m and +Ax m indicate the depth of field in the X-Y cross-section as to each light-emitting point
• the intervals between the solid lines - ⁇ 3 and + ⁇ 3 indicate the depth of field in the Z-X cross-section as to each light-emitting point.
• the depth of field in the X-Y cross-section changes at each light-emitting point position, while the depth of field in the Z-X cross-section is constant regardless of light-emitting point position.
• Fig. 4A is a pattern where the depth of field in the X-Y cross-section and the depth of field in the Z-X cross-section have been made the same at light-emitting point positions where the depth of field in the X-Y cross- section is the maximum.
• the common depth of field is equal to the narrowest depth of field in the X-Y cross-section, so light available efficiency is lost only regarding the difference between the common depth of field and the narrowest depth of field in the X-Y cross-section.
• Fig. 4A is a pattern where the depth of field in the X-Y cross-section and the depth of field in the Z-X cross-section have been made the same at light-emitting point positions where the depth of field in the X-Y cross- section is the maximum.
• the common depth of field is equal to the narrowest depth of field in the X-Y cross-section, so light available efficiency is lost only regarding the difference between the common depth of field and the narrowest depth of field in the X-Y cross-section.
• 4B is a pattern where the depth of field in the X-Y cross-section and the Z-X cross-section have been made the same at light-emitting point positions where the depth of field in the X-Y cross-section is the narrowest.
• the common depth of field is equal to the narrowest depth of field in the X-Y cross-section and the narrowest depth of field in the Z-X cross-section, so light available efficiency is lost only regarding the difference between the common depth of field and the widest depth of field in the X-Y cross-section.
• the optical apparatus according to the present embodiment is designed such that the depth of field is approximately the same in the X-Y cross-section and Z-X cross-section when the depth of field is narrowest in X-Y cross-section, i.e., when the light- emitting points at intermediate object height in the lens optical system 105a are imaged on the light-receiving surface 106.
• the depth of field is smallest in the present embodiment when light-emitting points in intermediate object height are imaged on the light-receiving surface 106.
• the half-value 0 m of the maximum value of the angle of divergence of the imaging optical flux in the X-Y cross-section is 13.46 degrees
• the half- value 0 S of the maximum value of the angle of divergence of the imaging optical flux in the Z-X cross-section is 21.14 degrees.
• the imaging optical system 105 forms same-size images of each of the light-emitting points of the light source 101 on the light-receiving surface 106, in each of the X-Y cross-section and Z-X cross-section.
• the image size D m on the light-receiving surface 106 in the X-Y cross-section is 42.30 ⁇ which is equal to the size of the light-emitting points
• the image size D s on the light-receiving surface 106 in the Z-X cross-section is 25.40 ⁇ which is equal to the size of the light-emitting points.
• resolution P is evaluated as 11.81 lp/mm (equivalent to 600 dpi) in the X-Y cross-section and Z-X cross-section.
• Figs. 5A and 5B are diagrams illustrating depth properties of the imaging optical system 105 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section.
• Fig. 5A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light- receiving surface 106.
• the depth of field in the X-Y cross- section is greater than the depth of field in the Z-X cross- section at each contrast value.
• Fig. 5B illustrates the relationship between depth of field and contrast when a light-emitting point at intermediate object height is imaged on the light-receiving surface 106.
• the depth of field in the X-Y cross-section and the depth of field in the Z-X cross-section are generally the same at each contrast value.
• Table 2 illustrates the depth of field for each of in the X-Y cross-section and in the Z-X cross-section for each contrast and the ratio thereof, when a light-emitting point at intermediate object height is imaged on the light- receiving surface 106.
• Table 2 shows that the depth of field is
• Expression (5) has been derived taking into consideration the depth of field when contrast is 100%, so from that perspective, confirmation should be made that the depth of field is the same (approximately equal) in both cross- sections at contrast of 100%. However, as mentioned earlier, confirming at contrast of 100% is difficult, due to
• the ratio of depth of field in both cross-sections is preferably evaluated at contrast of 80 to 90%, taking into
• the optical apparatus according to the present embodiment can provide good imaging
• the depth of field at the time of the imaging optical system 105 imaging light-emitting points at intermediate object height on the light-receiving surface 106 is approximately equal in the X-Y cross-section and in the Z-X cross-section .
• conditional expression taking into consideration the maximum number of lens optical systems 105a through which light rays from one light-emitting point of the light source 101 pass. Since the number of lens optical systems 105a through which light rays pass in the Z-X cross-section do not change with the present embodiment, we will consider only the maximum number of lens optical systems 105a through which light rays from one light-emitting point pass in the X-Y cross-section.
• n m 1 + integer portion (2 x L/p) , where L represents the maximum object height regarding which one lens optical system 105a can take in light rays, and p represents the array pitch of lens optical systems.
• L represents the maximum object height regarding which one lens optical system 105a can take in light rays
• p represents the array pitch of lens optical systems.
• tan0 m in the X-Y cross-section described above is expressed as in the following Expression (8), by the array pitch p in the first direction of the lens optical systems 105a, the maximum value n m of the number of lens optical systems 105a through which light rays pass, and distance 1 between the imaging unit 104 and light-receiving surface 106.
• tan0 s in the Z-X cross-section is expressed as in the following Expression (9), by the maximum effective width (valid width) T of the imaging optical system 105 in the second direction, and distance 1 between the imaging unit 104 and light-receiving surface 106.
• the maximum effective width T of the imaging optical system 105 in the second direction is the maximum width of the region which imaging optical fluxes pass
• T.he maximum effective width T of the imaging optical system 105 in the second direction is equal to the aperture width (aperture size) in the second direction of the lens optical systems 105a, in a configuration where only one lens row is arrayed in the second direction, as with the imaging optical system 105 according to the present embodiment.
• Expression (5) can be transformed as Expression (10) by Expressions (8) and (9).
• the array pitch p, the maximum number n m of lens optical systems 105a through which light rays from one light-emitting point pass, and the maximum effective width T of the imaging optical system 105 in the second direction, are set with the present embodiment so as to satisfy
• Expression (11) is even more preferable, in order to
• the array pitch p of the lens optical systems 105a is 0.77 mm in the present embodiment, and the maximum effective width T of the imaging optical system 105 in the . second direction is 2.44 mm, which is equal to the aperture size of the lens optical system 105a. Also, the maximum number n m of lens optical systems 105a through which light rays from one light-emitting point pass is two, taking into consideration light rays from light-emitting points at intermediate object height where depth of field is minimal.
• the values of Pi and Di are as described above. Substituting these values into the middle member of Expression (10) yields the following Expression (12), so it can be seen that conditional Expressions (10) and (11) are satisfied.
• Expression (8) includes approximation, and there is no difference in the fundamental idea.
• the lens optical systems of the lens optical systems of the optical apparatus according to the present embodiment are designed so as to satisfy
• the depth of field at the time of light-emitting points at intermediate object height being imaged on the light- receiving surface 106 is approximately equal in the X-Y cross-section and in the Z-X cross-section, thereby
• the present embodiment differs from the first embodiment with regard to the size of each of the light- emitting points of the light source 101, and the aperture size of the lens portion which the imaging unit 104 has, in the Z-X cross-section.
• the optical apparatus according to the present embodiment is of a configuration where the size of the light-emitting points of the light source is equal in the X-Y cross-section and in the Z-X cross-section, i.e., the resolution in both cross-sections is equal, and also the aperture size A s of the lens portion at the imaging unit 104 is changed as compared to that in the first embodiment.
• the aperture size A s in the second direction at the imaging units i.e., the maximum effective width T of the imaging optical system 105 in the second direction, is 1.70 mm in the present embodiment. Accordingly, the maximum value of the maximum half-value ⁇ 3 of the angle of divergence of the imaging optical flux in the Z-X cross-section, at the time of input of light rays from light-emitting points at intermediate object height to the light-receiving surface 106, is 15.07 degrees.
• the other values such as the maximum number n m of lens optical systems 105a through which light rays from one light-emitting point pass, are unchanged from the first embodiment. Accordingly, substituting these values into the middle member of
• Figs. 6A and 6B are diagrams illustrating depth properties of the imaging optical system 105 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section, in the same way as with Figs. 5A and 5B.
• Fig. 6A illustrates the relationship between depth of field of light rays from a light-emitting point at axial object height, and contrast, and in the same way as with Fig. 5A, the depth of field in the X-Y cross-section is greater than the depth of field in the Z-X cross-section at each contrast value.
• Fig. 6B illustrates that the depth of field in the X-Y cross-section and in the Z-X cross-section is approximately equal, due to the
• Table 3 illustrates the depth of field for each of in the X-Y cross-section and in the Z-X cross-section for each contrast and the ratio thereof, when a light-emitting point at intermediate object height is imaged on the light- receiving surface 106.
• the optical apparatus according to the present embodiment can make the depth of field in the X-Y cross-section and in the Z-X cross-section to be the same when a light-emitting point at intermediate object height is being imaged on the light-receiving surface 106, by being configured so as to satisfy conditional Expression (5) and conditional Expression (10) .
• the present embodiment differs from the first embodiment with regard to the values of the maximum object height L regarding which one lens optical system can take in light rays, and the array pitch p of the imaging optical system. Properties of the imaging optical system according to the present embodiment are shown in Table 4.
• Fig. 7A is a diagram illustrating the way in which a light-emitting point 701a at axial object height is imaged at the light-receiving surface 706 in the X-Y cross-section.
• Light rays emitted from the light-emitting point 701a are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 702, and subsequently condensed on the light-receiving surface 706 by way of the imaging unit 704.
• the light rays emitted from the light- emitting point 701a passes through three lens portions at each of the imaging units 702 and 704.
• the number of lens optical systems 705a which the light rays emitted from the light-emitting point at axial object height pass through is three. It can be seen from Fig. 7A that a great part of the light rays is input to the lens optical system 705a at the middle (i.e., on the axis where the light-emitting point 701a is situated) , while the amount of light rays input to the two lens optical systems 705a on either side of this lens optical system 705a is scant.
• Fig. 7B is a diagram
• a light-emitting point 701b at intermediate object height is imaged on the light-receiving surface 706 in the X-Y cross-section.
• Light rays emitted from the light-emitting point 701b are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 702, in the same way as with light rays emitted from the light-emitting point 701a, and subsequently condensed on the light-receiving surface 706 by way of the imaging unit 704.
• the light rays emitted from the light- emitting point 701b pass through two lens portions at each of the imaging units 702 and 704. That is to say, the number of lens optical systems 705a which the light rays emitted from the light-emitting point at intermediate object height pass through is two.
• the imaging optical system 705 here is an inverted same-size imaging system in the Z-X cross- section, so the number of lens rows of the lens optical system 705a which light rays emitted from the light-emitting point 701a pass through is the number of lens rows in the second direction.
• the number of lens rows in the second direction is one row, so light rays emitted from the light-emitting point 701a only pass through one lens optical system 705a.
• the half-value of the incident angle of an extreme periphery light ray 707sa of the light rays passing through that lens optical system 705a when entering the light-receiving surface 706, i.e., the half-value of the angle of divergence of the imaging optical flux of the light rays emitted from the light- emitting point 701a is 6 sa of 20.27 degrees.
• light rays emitted from the light-emitting point 701b become approximately parallel light by way of the imaging unit 702, and then are input to the imaging unit 704 and condensed on the light-receiving surface 706, as
• Fig. 7D Accordingly, light rays emitted from the light-emitting point 701b also only pass through one lens optical system 705a, in the same way as with light rays emitted from the light-emitting point 701a.
• the half-value of the incident angle of an extreme periphery light ray 707sb of the light rays passing through that lens optical system 705a when entering the light-receiving surface 706, i.e., the half-value of the angle of divergence of the imaging optical flux of the light rays emitted from the light-emitting point 701b is 9 sb of 20.27 degrees, the same as with 0 sa .
• the maximum number of lens optical systems 705a through which light rays from one light-emitting point pass is 0.87 mm, and the array pitch p of lens optical systems 705a is 0.76.
• n m the maximum number of lens optical systems 705a through which light rays from one light-emitting point pass in the X-Y cross-section
• integer portion (2 x L/p) 3.
• n m is an odd number, so the half-value 9 ms of the angle of divergence is the maximum (maximum value) when an imaging optical flux from a light-emitting point at intermediate object height is input to the light-receiving surface 706. Accordingly, the half-value of the incident angle of an extreme periphery light ray 707ma of the light rays passing through three lens optical systems 705a in X-Y cross-section, when entering the light-receiving surface 706, is 0 ma of
• the maximum number of lens optical systems 705a through which light rays from one light-emitting point pass in the Z-X cross-section is n s of one, and the half-value of the angle of divergence of the imaging optical flux in X-Y cross-section, is 6 S of 20.27 degrees.
• the aperture size A s of the imaging units in the second direction i.e., the maximum effective width T of the imaging optical system 705 in the second direction is 2.44 mm.
• Expressions (17) and (18) do not satisfy Expressions (5) and (10) .
• FIGs. 8A and 8B are diagrams illustrating depth properties of the imaging optical system 705 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section, the same as with Figs. 5A and 5B.
• Fig. 5A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light-receiving surface 706, and in the same way as with the case of Fig. 5A, the depth of field in the X-Y cross-section is greater than the depth of field in the Z-X cross-section at each contrast value.
• Fig. 5A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light-receiving surface 706, and in the same way as with the case of Fig. 5A, the depth of field in the X-Y cross-section is greater than the depth of field in the Z-X cross-section at each contrast value.
• FIG. 8B illustrates that the depth of field in the X-Y cross-section and in the Z-X cross-section are generally the same, due to the relationship between depth of field and contrast when a light-emitting point at intermediate object height is imaged on the light-receiving surface 706.
• Table 5 illustrates the depth of field for each of in the X-Y cross-section and in the Z-X cross-section for each contrast and the ratio thereof, when a light-emitting point at intermediate object height is imaged on the light- receiving surface 706.
• Table 5 shows that the depth of field in the X-Y cross-section and in the Z-X cross-section is made
• conditional Expressions (5) and (10) derived assuming depth of field at contrast of 100% were used by approximating as conditional expression
• Expressions (5) and (10) need to be created assuming a case of performing evaluation with depth of field at contrast of 40% to 80%.
• Fig. 9 illustrates the relation between object height as to a certain lens optical system 705a of the imaging optical system 705, and light available efficiency.
• the amount of light which can be taken in increases as the object height where the light- emitting point is situated increases, and light rays cannot be taken in from an object height greater than the maximum object height L.
• ⁇ assuming contrast of 100% an object height where the light rays taken into the lens optical system 705a are scant, also has to be taken into consideration.
• the lens optical system 705a has to be deemed to not take in light rays with regard to an object height of which the amount of light is not greater than a predetermined amount.
• an effective maximum object height (a valid maximum object height) L 1 at which one lens optical system 705a can take in light rays, when assuming contrast of 40 to 80%, is defined with the present embodiment.
• the ⁇ ' is then defined from ni' which is the maximum effective number (valid number) of lens optical systems 705a through which light rays for the object heights at or lower than the effective maximum object height L 1 , and the half-value ⁇ 1 of the effective angle (valid angle) of diversion of the
• n m ' the maximum effective number of lens optical systems 705a through which light rays from one light-emitting point pass in the X-Y cross-section
• integer portion (2 x 0.85 L/p) 2.
• n m ' is an even number, so the half-value 0 m ' of the angle of divergence is the maximum (maximum value) when an imaging optical flux from a light-emitting point at
• the half-value of the maximum value of the effective angle of divergence of the imaging optical flux in X-Y cross-section is 9 m ' of 13.98 degrees.
• the maximum effective number of lens optical systems 705a through which light rays from one light-emitting point pass in the Z-X cross-section is n s ' of one, and the half-value of the
• the maximum effective angle of divergence of the imaging optical flux is ⁇ 3 ' of 21.31 degrees.
• the aperture size A s of the imaging units in the second direction i.e., the maximum effective width T of the imaging optical system 705 in the second direction is 2.44 mm.
• each lens optical system is an enlarging optical system in Z-X cross-section, and the light-emitting point size in Z-X cross-section and the image on the light- receiving surface are not the same size.
• FIGs. 10A through 10D are schematic diagrams of principal portions of an optical apparatus according to the present embodiment, with Figs. 10A and 10B illustrating the X-Y cross-section, and Figs. IOC and 10D illustrating the Z- X cross-section.
• the optical apparatus according to the present embodiment includes a light source 1001 including multiple light-emitting points arrayed on an object plane, and an imaging optical system 1005 which condenses multiple light rays emitted from the light source 1001 upon a light- receiving surface (image plane) 1006.
• the imaging optical system 1005 is a lens array including multiple lens optical systems 1005a arrayed in the first direction, and shielding portions 1003 to shield stray light rays.
• the optical systems 1005a include imaging units 1002 and 1004 disposed on the same optical axis. Note that unlike the first embodiment, the lens portions making up the imaging unit 1002 and the lens portions making up the imaging unit 1004 are of different shapes. Thus, the imaging optical system 1005 according to the present
• Lens surfaces 1002a and 1002b, of the imaging unit 1002, and 1004a and 1004b, of the imaging unit 1004 all have
• anamorphic aspheric forms (anamorphic surfaces) .
• the aspheric forms thereof are expressed in Expression (1) described above.
• Fig. 10A is a diagram illustrating the way in which a light-emitting point 1001a at axial object height in the X-Y cross-section is imaged on the light-receiving surface 1006 by the imaging optical system 1005.
• Fig. 10B is a diagram illustrating the way in which a light-emitting point 1001b at intermediate object height in X-Y cross-section is imaged on the light-receiving surface 1006.
• Light rays emitted from the light-emitting points 1001a and 1001b are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 1002, and subseguently condensed on the light-receiving surface 1006 by way of the imaging unit 1004.
• the light rays emitted from the light-emitting point 1001a each only pass through one lens optical system 1005a, while the light rays emitted from the light-emitting point 1001b each pass
• the half-value of the angle of divergence of the light rays emitted from the light-emitting point 1001a is 0 ma of 7.31 degrees
• the half-value of the angle of divergence of the light rays emitted from the light-emitting point 1001b is G m b of 13.49 degrees.
• the half-value 0 m of the angle of divergence of the optical flux changes depending on the position of the light- emitting point in the X-Y cross-section, so the depth of field differs depending on the position of the light- emitting point.
• light rays emitted from the light-emitting points 1001a and 1001b become parallel light by way of the imaging unit 1002, and then are input to the imaging unit 1004 and condensed on the light-receiving surface 1006, as illustrated in Figs. 7C and 7D.
• the imaging optical system 1005 here is an inverted same-size imaging system in the Z-X cross-section, so the light rays emitted from each of the light-emitting points 1001a and 1001b only pass through one lens optical system 1005a.
• the half-value of the angle of divergence of the imaging optical fluxes of the light rays emitted from the light-emitting points 1001a and 1001b is Q sa and 9 sb both of 17.23 degrees.
• the half- value 0 S is constant regardless of the position of the light- emitting points, so the half-value of the incident angle of an imaging optical flux is also constant regardless of the position of the light-emitting points.
• the optical apparatus is designed such that the depth of field when light-emitting points at intermediate object height are imaged on the light-receiving surface 1006 is approximately equal in the X- ⁇ Y cross-section and in the Z-X cross-section.
• the smallest depth of field in the X-Y cross-section and the depth of field in the Z-X cross-section can be made to be approximately equal, so imaging capabilities can be stabilized while securing maximal light.
• n m and n m ' are equal, so advantages of the present invention can be obtained with a configuration satisfying conditional Expressions (5) and (10) in both cases of taking in to consideration contrast of 100% and contrast of 40 to 80%.
• n m is an even number, so the half-value 0 m of the angle of divergence is the maximum (maximum value) when an imaging optical flux from a light- emitting point at intermediate object height is input to the light-receiving surface 1006. Accordingly, the half-value of the maximum value of the incident angle of an imaging optical flux in X-Y cross-section is 13.49 degrees.
• the maximum number of lens optical systems 1005a through which light rays from one light-emitting point pass in the Z-X cross-section is n s of one, and the half-value of the maximum value of the angle of divergence of the imaging optical flux, is 0 S of 17.23 degrees.
• the aperture size A s of the imaging units in the second direction i.e., the maximum effective width T of the imaging optical system 1005 in the second direction is 2.44 mm.
• the imaging optical system 1005 forms same-size images of each of the light-emitting points of the light source 1001 on the light- receiving surface 1006, in the X-Y cross-section and Z-X cross-section.
• the image size D m on the light- receiving surface 1006 in the X-Y cross-section is 42.30 ⁇ which is equal to the size of the light-emitting points.
• the imaging optical system 1005 performs enlarged imaging of the light-emitting points of the light source 1001 by a power of 1.3, so image size D s on the light-receiving surface 1006 in the Z-X cross-section is 13 085017
• resolution P is evaluated as 11.81 lp/mm
• conditional Expression (10) The reason why the present embodiment does not satisfy conditional Expression (10) is that the imaging optical system 1005 according to the present embodiment is an enlarging optical system, so approximation in Expression (8) described above does not hold. In this way, conditional Expression (10) cannot be applied unless with an optical system where (8) holds.
• Figs. 1LA and 11B are diagrams illustrating depth of field properties of the imaging optical system 1005 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section.
• Fig. 11A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light-receiving surface 1006, and in the same way as with Fig. 5A, the depth of field in the X-Y cross-section is greater than the depth of field in the Z-X cross-section at each contrast value.
• Fig. 11B is diagrams illustrating depth of field properties of the imaging optical system 1005 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section.
• Fig. 11A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light-receiving surface 1006, and in the same way as with Fig. 5A, the depth of field in the X-
• Table 7 illustrates the depth of field for each of in the X-Y cross-section and in the Z-X cross-section for each contrast and the ratio thereof, when a light-emitting point at intermediate object height is imaged on the light- receiving surface 1006.
• Table 7 shows that the depth of field can be made approximately equal in the X-Y cross-section and in the Z-X cross-section, in the contrast range of 40 to 80%.
• the depth of field in the X-Y cross-section and in the Z-X cross-section can be made the same when a light-emitting point at intermediate object height is being imaged on the light-receiving surface 106, by configuring the optical apparatus according to the present embodiment so as to satisfy conditional Expression (5).
• FIGs. 12A. through 12D are schematic diagrams of principal portions of an optical apparatus according to the present embodiment, with Figs. 12A and 12B illustrating the X-Y cross-section, and Figs. 12C and 12D illustrating the Z- X cross-section.
• the optical apparatus according to the present embodiment includes a light source 1201 including multiple light-emitting points arrayed on an object plane, and an imaging optical system 1205 which condenses multiple light rays emitted from the light source 1201 upon a light- receiving surface (image plane) 1206.
• the imaging optical system 1205 is a lens array including multiple lens optical systems 1205a arrayed in the first direction, and shielding portions 1203 to shield stray light rays.
• the optical systems 1205a include imaging unit 1202 and 1204 disposed on the same optical axis.
• the imaging units 1202 and 1204 each have lens portions of the same form arrayed at equal intervals in the first direction at equal intervals, and the imaging units 1202 and 1204 are
• Lens surfaces 1202a and 1202b, of the imaging unit 1202, and 1204a and 1204b, of the imaging unit 1204 all have anamorphic aspheric forms (anamorphic surfaces) .
• the aspheric forms thereof are expressed in Expression (1) described above.
• Fig. 12A is a diagram illustrating the way in which a light-emitting point 1201a at axial object height in the X-Y cross-section is imaged on the light-receiving surface 1206 by the imaging optical system 120
• Fig. 12B is a diagram illustrating the way in which a light-emitting point 1201b at intermediate object height in X-Y cross-section is imaged on the light-receiving surface 1206 by the imaging optical system 1205.
• Light rays emitted from the light- emitting points 1201a and 1201b are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 1202, and subsequently condensed on the light-receiving surface 1206 by way of the imaging unit 1204.
• the present embodiment differs from the first embodiment with regard to the point that the light rays emitted from the light-emitting point 1201a pass through three lens optical systems 1205a, and the light rays emitted from the light-emitting point 1201b pass through four lens optical systems 1205a.
• the half-value of the angle of divergence of the light rays emitted from the light-emitting point 1201a is G ma of 11.81 degrees
• the half-value of the angle of divergence of the light rays emitted from the light-emitting point 1201b is of 15.59 degrees.
• the half-value 0 m of the angle of divergence of the optical flux changes depending on the position of the light-emitting point in the X-Y cross-section, so the depth of field differs depending on the position of the light-emitting point .
• the half-value of the angle of divergence of the imaging optical fluxes of the light rays emitted from the light-emitting points 1201a and 1201b is 9 sa and Q sb both of 22.47 degrees.
• the half-value 0 S of the incident angle of an imaging optical flux is constant regardless of the position of the light-emitting points, so the depth of field is also constant regardless of the position of the light-emitting points.
• the depth of field of the imaging optical system 1205 in the X-Y cross-section differs depending on the position of the light-emitting points, the depth of field in the Z-X cross-section is constant
• the optical apparatus is designed such that the depth of field when light-emitting points at intermediate object height are imaged on the light-receiving surface 1206 is approximately equal in the X-Y cross-section and in the Z-X cross-section.
• the smallest depth of field in the X-Y cross-section and the depth of field in the Z-X cross-section can be made to be approximately equal, so imaging capabilities can be stabilized while securing maximal light.
• the maximum number of lens optical systems 1205a through which light rays from one light-emitting point pass is 1.035 mm
• the array pitch p of lens optical systems 1205a is 0.52.
• n m the maximum number of lens optical systems 1205a through which light rays from one light-emitting point pass in the X-Y cross-section
• n m ' the maximum number of lens optical systems 1205a through which light rays from one light-emitting point pass in the X-Y cross-section
• n m ' the maximum number of lens optical systems 1205a through which light rays from one light-emitting point pass in the X-Y cross-section
• n m is an even number
• the half-value 9 m of the angle of divergence is the maximum (maximum value) when an imaging optical flux from a light- emitting point at intermediate object height is input to the light-receiving surface 1206.
• the half-value of the maximum value of the incident angle of an imaging optical flux in X-Y cross-section is 15.59 degrees.
• the maximum number of lens optical systems 1205a through which light rays from one light-emitting point pass in the X-Y cross-section is n s of one, and the half-value of the angle of divergence of the imaging optical flux, is ⁇ 3 of 22.47 degrees.
• the maximum effective width T of the imaging optical system 1205 in the second direction is 2.44 mm.
• the imaging optical system 1205 forms same-size images of each of the light-emitting points of the light source 1201 on the light- receiving surface 1206, in each of the X-Y cross-section and Z-X cross-section.
• the image size D m on the light- receiving surface 1206 in the X-Y cross-section is 42.30 ⁇ which is equal to the size of the light-emitting points.
• the image size D s on the light-receiving surface 1206 in the Z-X cross-section is the same 25.40 ⁇ .
• resolution P is evaluated as 11.81 lp/mm (equivalent to 600 dpi) in the X-Y cross-section and Z-X cross-section.
• FIGs. 13A and 13B are diagrams illustrating depth properties of the imaging optical system 1205 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section, in the same way as with the first
• Fig. 13A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light-receiving surface 1206, and in the same way as with Fig. 5A, the depth of field in the X-Y cross-section is greater than the depth of field in the Z-X cross-section at each contrast value.
• Fig. 13B illustrates that the depth of field in the X-Y cross-section and in the Z-X cross-section is approximately equal, due to the relationship between depth of field and contrast, when a light-emitting point at intermediate object height is imaged on the light-receiving surface 1206.
• Table 9 illustrates the depth of field for each of in the X-Y cross-section and in the Z-X cross-section for each contrast and the ratio thereof, when a light-emitting point at intermediate object height is imaged on the light- receiving surface 1206.
• Table 9 shows that the depth of field can be made approximately equal in the X-Y cross-section and in the Z-X cross-section, in the contrast range of 40 to 90%.
• n m and n m ' are preferably four or less, taking into consideration the imaging capabilities of the lens optical system.
• the present embodiment is a configuration where the lens optical systems according to the first embodiment have been divided into top and bottom, and one thereof shifted in the first direction by half-pitch of the lens optical systems.
• Figs. 14A through 14C are schematic diagrams of principal portions of an optical apparatus according to the present embodiment.
• Fig. 14A illustrates the X-Y cross- section
• Fig. IB illustrates the Z-X cross-section
• Fig. 14C is a frontal view from the X direction.
• the optical apparatus according to the present embodiment includes a light source 1401 including multiple light-emitting points arrayed on an object plane, and an imaging optical system 1405 which condenses multiple light rays emitted from the light source 1401 upon a light-receiving surface 1406.
• the imaging optical system 1405 is a lens array including multiple lens optical systems 1405a arrayed in the first direction, and shielding portions 1403 to shield stray light rays.
• the lens optical systems 1405a include imaging units 1402 and 1404 situated on the same optical axis.
• the imaging units 1402 and 1404 each include two lens rows in the second direction.
• Each lens row is configured of multiple lens portions of the same shape being arrayed in the first direction at equal
• the two lens rows making up each of the imaging units 1402 and 1404 are configured such that the lens row making up each imaging unit in the first embodiment is divided top and bottom and shifted in the first direction by a half-pitch of the lens unit array interval.
• the imaging unit 1402 and imaging unit 1404 are situated symmetrically as to the optical axis direction.
• Lens surfaces 1402a through 1402d of the imaging unit 1402 and lens surfaces 1404a through 1404d of the imaging unit 1404 each have anamorphic aspheric forms (anamorphic surfaces). The aspheric forms thereof are expressed in Expression (1) described above.
• Fig. 15A is a diagram illustrating the way in which a light-emitting point 1401a at axial object height in the ⁇ - ⁇ cross-section is imaged on the light-receiving surface 1406 by the imaging optical system 1405.
• Fig. 15B is a diagram illustrating the way in which a light-emitting point 1401b at intermediate object height in Z-X in X-Y cross- section is imaged on the light-receiving surface 1406.
• the present embodiment differs from the other embodiments described above with regard to the positions of the light-emitting points 1401b at intermediate object height. Specifically, the light-emitting points 1401b are not situated at intermediate positions between optical axes of lens optical systems 1405a adjacent in the first
• lens optical systems 1405a have a configuration of being divided top and bottom and shifted by half-pitch.
• Light rays emitted from each of the light-emitting points 1401a and 1401b are temporarily condensed at the intermediate imaging plane A by way of the imaging unit 1402, and subsequently condensed on the light-receiving surface 1406 by way of the imaging unit 1404.
• the half-values of the angles of divergence of the light rays emitted from the light-emitting points 1401a and 1401b in the X-Y cross- section are 6 ma and of 7.32 degrees and 13.38 degrees, respectively.
• the optical apparatus is designed such that the depth of field when light-emitting points at intermediate object height are imaged on the light-receiving surface 1406 is approximately equal in the X-Y cross-section and in the Z-X cross-section.
• the smallest depth of field in the X-Y cross-section and the depth of field in the Z-X cross-section can be made to be approximately equal, so imaging capabilities can be stabilized while securing maximal light.
• n m which is the maximum number of lens optical systems 1405a through which light rays from one light- emitting point pass in the X-Y cross-section
• aperture size A m of the lens optical system 1405a in the first direction are taken into consideration. Specifically, we will consider application of Expression (10) to a lens row where the value of n m x A m is maximum.
• the maximum object height L regarding which one lens optical system 105a can take in light rays is 0.768 mm, and the array pitch p of lens optical systems 1405a is 0.77 mm.
• n m the maximum number of lens optical systems 705a through which light rays from one light-emitting point pass in the X-Y cross-section
• the value of n m x A m is equal for the upper and lower lens optical systems 1405a in the present
• n m is an even number
• the half-value 9 ms of the angle of divergence is the maximum (maximum value) when an imaging optical flux from a light- emitting point at intermediate object height is input to the light-receiving surface 1406.
• the half-value of the maximum value of the incident angle of an imaging optical flux in X-Y cross-section is 13.38 degrees.
• the maximum number of lens optical systems 1405a through which light rays from one light-emitting point pass in the Z-X cross-section is n s of two
• the half-value of the angle of divergence of the imaging optical flux is 0 S of 21.14 degrees
• the aperture size A s of the lens optical systems 1405a for the upper and lower lens rows is 1.22 mm, so the maximum
• effective width T of the imaging optical system 1405 in the second direction is 2.44 mm.
• the imaging optical system 1405 forms same-size images of each of the light-emitting points of the light source 1401 on the light- receiving surface 1406, in each of the X-Y cross-section and Z-X cross-section.
• the image size D m on the light- receiving surface 1406 in the X-Y cross-section is 42.30 ⁇ which is equal to the size of the light-emitting points
• the image size D s on the light-receiving surface 1406 in the Z-X cross-section is 25.40 ⁇ which is equal to the size of the light-emitting points.
• resolution P is evaluated as 11.81 lp/mm (equivalent to 600 dpi) in the X-Y cross-section and Z-X cross-section .
• FIGs. 16A and 16B are diagrams illustrating depth properties of the imaging optical system 1405 according to the present embodiment in the X-Y cross-section and in the Z-X cross-section, in the same way as with the first
• Fig. 16A illustrates the relationship between depth of field and contrast when a light-emitting point at axial object height is imaged on the light-receiving surface 1406.
• Fig. 16B illustrates the relationship between depth of field and contrast when a light-emitting point at intermediate object height of each lens optical system 1405a is imaged on the light-receiving surface 1406.
• Fig. 16B illustrates that the depth of field in the X-Y cross-section and in the Z-X cross-section is approximately equal.
• Table 11 illustrates the depth of field for each of in the X-Y cross-section and in the Z-X cross-section for each contrast and the ratio thereof, when a light-emitting point at intermediate object height is imaged on the light- receiving surface 1406.
• Table 11 shows that the depth of field can be made approximately equal in the X-Y cross-section and in the Z-X cross-section, in the contrast range of 70 to 100%.
• the depth of field in the X-Y cross-section and in the Z-X cross-section can be made the same when a light-emitting point at intermediate object height is being imaged on the light-receiving surface 1406, by configuring the optical apparatus according to the present embodiment so as to satisfy conditional Expressions
• Fig. 17 is a schematic diagram (Z-X cross-sectional view) of principal portions of a color image forming
• the color image forming apparatus 33 is a tandem-type color image forming apparatus, which has four of any one of the optical apparatuses (exposure units)
• the color image forming apparatus 33 includes optical apparatuses 17, 18, 19, and 20, having one of the configurations illustrated in the embodiments, photosensitive drums 21, 22, 23, and 24, serving as image carrying members, developing units 25, 26, 27, and 28, a conveying belt 34, and a fixing unit 37.
• the optical apparatuses 17, 18, 19, and 20 are each disposed such that the second direction of the imaging optical systems matches the sub-scanning direction (Z direction) of the photosensitive drums 21, 22, 23, and 24, which is the direction of rotation thereof.
• the color image forming apparatus 33 receives input of color signals of R (red) , G (green) , and B (blue) , from external equipment 35 such as a personal computer or the like. These color signals are converted into image signals (dot data) of C (cyan) , M (magenta) , Y (yellow) , and K (black) by a printer controller 36 within the apparatus, and input to the respective optical signals
• the printer controller 36 controls each part of the color image forming apparatus 33, besides signal conversion.
• Exposure lights 29, 30, 31, 32 modulated in accordance with the color image signals is emitted from the optical apparatuses 17, 18, 19, and 20, respectively.
• the exposure lights 29, 30, 31, 32 expose the photosensitive surfaces of the photosensitive drums 21, 22, 23, and 24 charged by charging rollers omitted from illustration, forming electrostatic latent images on the photosensitive surfaces of each.
• the electrostatic latent images on the photosensitive surfaces of the photosensitive drums 21, 22, 23, and 24 developed by respective developing units 25, 26, 27, and 28, as toner images.
• the toner images of each color are transferred by overlaying onto a transfer medium, by a transferring unit omitted from illustration, and then fixed by the fixing unit, thereby completing one fill-color image.
• an optical apparatus is configured by a document being positioned at the object face of the imaging optical system, and a
• photoreceptor unit being positioned at the image plane
• a line sensor configured of a CCD sensor or CMOS sensor or the like, for example, may be used as the photoreceptor unit.
• a color digital photocopier may be configured by connecting the image reading apparatus as the above-described external equipment 35, to the color image forming apparatus 33.
• An image reading apparatus can irradiate a document by an illumination unit including a light source, condense optical fluxes (reflected light or transmitted light) on an imaging optical system, and receive light by a sensor face of the photoreceptor unit.
• the imaging optical system is positioned such that the second direction thereof matches the direction in which the relative position between the document and the imaging optical system is changed (sub-scanning direction) , whereby the document can be sequentially read in the sub-scanning direction.
• the illumination unit in the image reading apparatus is not restricted to a light source, an a configuration may be used where external light is guided to the original.
• the embodiments have been described above as configurations where Expression (5) is satisfied by innovating the designed aperture size of the lens portions in the first direction and second direction, but design methods for the optical apparatus to satisfy Expression (5) are not restricted to this.
• a configuration may be employed where innovation is made regarding size of the light-emitting points of the light source in the first direction and second direction to satisfy Expression (5) .
• the lens surfaces of the imaging optical system in the embodiments have aspheric forms expressed by Expression (1), but the present invention is not restricted to this, and aspheric forms expressed by other expressions may be employed. Also, while light-emitting points are imaged inverted on the light-receiving surface without intermediate imaging in the Z-X cross-section, the light- emitting points may be imaged erect on the light-receiving surface after intermediate imaging, as with the X-Y cross- section .
• an imaging optical system may be configured having three or more imaging units.
• an imaging unit in the sixth embodiment is of a configuration having two lens rows in the second direction, an imaging unit may be configured having three or more lens rows in the second direction.
• the light source according to the embodiments has been described as a configuration where multiple light-emitting points are arrayed in a first direction alone, a configuration may be employed where multiple rows of the light-emitting points are arrayed in the second direction, and the multiple light-emitting points are arrayed in a staggered layout.
• This configuration enables a greater number of light-emitting points to be densely arrayed without consideration of space to other light-emitting points adjacent in the first direction, so resolution can be further improved.
• the optical apparatus according to the above-described embodiments exhibits greater advantages in image formation apparatuses of 1200 dpi or higher.

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• Light Sources And Details Of Projection-Printing Devices (AREA)
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• 2012
  • 2012-12-27 JP JP2012284439A patent/JP6270314B2/ja not_active Expired - Fee Related
• 2013
  • 2013-12-18 KR KR1020157019406A patent/KR20150097732A/ko not_active Withdrawn
  • 2013-12-18 CN CN201380068231.XA patent/CN104884989A/zh active Pending
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